Hi guys and thanks for tuning in again
today we’ll be looking at the VAM-9020 digital meter.
I bought this meter from banggood for around $11 including shipping which is
not that bad of a deal considering all the functions and capabilities it has.
The main reason I bought it is hook it up to my DIY power supply kit that I made
in an earlier video. Link is in the description as well. Here are the
specifications. Its voltage range differs whether you are using an external power
supply to power the display. If you are then the voltage range goes from 0 to 90
volts. If you don’t use a power supply but instead rely on the power going
through the device then you are restricted to a minimum of 10 volts. It
can handle a decent amount of current 0 to 20 amps which is nice for pretty much
any electronics hobbyist like myself. Voltage and current accuracy could be
better but if you need more precise measurements you are going to have to
use a multimeter anyway. The refresh rate of the display is not
too bad either coming in at 5 times per second. The main unit is simple enough.
The front panel has three buttons on it UP, OUT and DOWN and the various modes are
displayed on the right side as well. The back of the display has four terminals.
The first terminal is used for the negative output wire, the second for the
positive input and positive output together and the fourth is used for the
negative input wire. If you want to use an external power supply to power the
unit, you need to add the negative wire coming from the power supply to the
first terminal and the positive to the third one. But before powering it up
there is one more step you need to do we need to do. Take apart the back plate of
display first by removing all the screws. Next we remove the small solder bridge
that is located above the terminals. Best way I
found to do this is with a vacuum pump and the soldering iron. Just make sure to
check with a multimeter set to continuity testing if you have indeed
removed the solder bridge successfully. Now it’s time to put everything back
together. Don’t forget to align all the plastic spacers correctly before putting
back the plate with the screws in place. Here are all the wires I’m going to use.
When you have everything set up you can start connecting them one by one. If you
connected everything together correctly after powering on your 12 to 60 volt
external power supply you should see the display come to life. Here you can see
that as I am adjusting the voltage on my power supply the voltage on the display
changes accordingly. For testing out the current I use the small 5 volt USB dummy
load which at 5 volts can draw 1 2 or 3 amps depending on which switch I turn on.
Last thing you have to do is to calibrate the display. There are 4
calibrations you need to do in order to get it set up correctly. 2 calibrations
for voltage one for below 20 volts and one for over 20 volts. To calibrate the
voltage press and hold the OUT button to go into calibration mode. You should see
0 – U for voltage calibration. Use the up and down arrows to correct the voltage.
Next press the OUT button 2 times until you see 2-ES on the top. Press UP once to
select YES on the bottom display and out one more time to save the changes. Do the same for the higher voltage as
well. Calibration of the current is basically the same. The break off point is
two amps. I used 150 milliamps to calibrate the low end and three amps to
calibrate the high end. Again press and hold the out button to go into the
calibration menu. Press out button again until you see 1-C and calibrate your low
amperage setting first using the up and down arrows. Once done press the Out
button again until you see 2-ES. Press the up arrow to select YES on the
bottom. Finally press out again to save your settings. Do the same for the higher
amps as well. And that’s it! now you have your VAM-9020 display connected and calibrated correctly. In one of my next videos I
will be installing this display in a case I am making for my DIY lab bench
power supply so please make sure you subscribe to see more interesting videos
like this in the future. If you have any questions or if something wasn’t clear
I’m always happy to answer anything in the comment section below. Thanks for
watching, I hope you learned something and I’ll see you in the next one!